The present invention relates to a user input device for entering alphanumeric data on a device having relatively few data entry keys, and more particularly to a keypad for entering alphanumeric data on a portable communication unit.
Portable electronic devices with text entry capabilities are increasing in usage. These devices are being built in smaller sizes each year. For many of these devices, such as cellular phones, models that are small in size are perceived as desirable by consumers. Cellular phone manufacturers have responded to this, and produce a variety of cellular phones that are small relative to earlier models, with some models being smaller than the size of a user""s palm.
Cellular phones have a number of features that require a user to input alphanumeric characters. A user may, for example, enter alphanumeric text in the name field of a phone list maintained in the phone. A user may also use a cell phone to send text messages via short messaging service (SMS) technology. To do this, a user generally inputs alphanumeric characters into the phone. Typically, a numeric keypad is used to enter alphanumeric characters, where the number of alphanumeric characters exceeds the number of numeric input keys.
A technique generally used to enter alphanumeric characters into a phone uses a standard alphabetic arrangement illustrated in FIG. 1. In this method a cellular phone has two data entry modes, a numeric mode and an alphanumeric mode. In the numeric mode, activation of the data entry keys represents numeric digits. The numeric digits are determined from the correspondence between each data entry key and the numeric digit associated with that key. In a standard telephone, activation of data entry keys in numeric mode generates dual tone multifrequency (DTMF) signals in accordance with an industry standard.
When operating in the alphanumeric mode, single activation of a data entry key is interpreted as a user selection of the first letter in the sequence of letters that are assigned to the particular data entry key. Similarly, when a data entry key is activated twice by a user, this is interpreted as a selection of the second letter in the sequence of letters associated with that particular data entry key. A timeout threshold is used to determine when selection of a character is complete. If a period of time equal to the timeout threshold follows the activation of a key without a subsequent activation of a key, the selection of the character is considered to be completed. Also, if the user activates a first key followed by an activation of a different key, the activation of the second key is considered to be the beginning of the selection of a new character.
With this method, a user may activate a key one, two, three, or four times in order to select a particular letter of the alphabet. Multiple activations of keys increase the time required to enter text using the keypad.
In addition to use of the keys to enter alphanumeric data, letters on keys assist users in entering telephone numbers or other numeric data. Some telephone numbers are represented by mnemonic phone numbers, in which at least part of the phone number is specified by the use of letters, to assist in memorization of the number. For example, 1-800-ABCDEFG is equivalent to 1-800-2223334, when a user activates each key once for each number or letter in the mnemonic phone number.
Because entry of alphanumeric characters on a limited keypad is less efficient than on a full sized keyboard, a mechanism for improving the efficiency is desirable. Changes to increasing efficiency can be problematic because users are familiar with the standard key mapping. Also, the use of mnemonic telephone numbers is a further consideration.
The present invention provides an apparatus for data entry of a plurality of letters of an alphabet. In one aspect of the invention, the apparatus includes a plurality of data entry keys and a memory having a key mapping. The key mapping represents a correspondence between each of the data entry keys and a corresponding ordered set of letters based on an alphabetical ordering of the plurality of letters. The ordering of letters within each ordered set is based on a decreasing frequency of use of each character. The apparatus also includes a processor coupled to the memory and the data entry keys, the processor receiving signals representing activations of one of the data entry keys. The processor determines a selected character corresponding to the activations of the data entry key, based on the key mapping and the signals representing activation, wherein the number of activations corresponding to the selected character is based on the position of the selected character within its respective group.
In another aspect of the invention, the letters within each group of letters are adjacent to each other in the alphabet. Each letter within a group of letters precedes each letter within a group associated with a higher numbered data entry key.
In yet another aspect of the invention, at least one group of letters comprises an ordered set of letters in order of decreasing frequency of use and is not in alphabetical order. In an additional aspect of the invention, most of the groups of letters comprise an ordered set of letters in order of decreasing frequency of use and not in alphabetical order.
In yet another aspect of the invention, an indicia for each letter is located in physical association with a corresponding data entry key.
In still another aspect of the invention, each data entry key has a corresponding ordered set of letters, a selected letter is determined to be a first letter of the ordered set of letters if one activation of the data entry keys is detected, the selected letter is determined to be the second letter if two activations of the data entry keys are detected, and the selected letter is determined to be the third letter if three activations of the data entry keys are detected.
In yet still another aspect of the invention, the apparatus includes 8 data entry keys, each key having 3 or more letters in a corresponding ordered set of letters.
In a further aspect of the invention, the apparatus includes a transmitter that transmits a sequence of characters, wherein each character of the sequence of characters is determined by the processor in response to a sequence of activations of the data entry keys.
In a still further aspect of the invention, a device receives signals representing activations from a plurality of input keys, and a selected character is determined based on a key mapping. The key mapping maps each input key and each activation count to a letter corresponding to the input key. The letters are ordered on the input keys in decreasing order of frequency of use.
In yet another further aspect of the invention, the group of letters corresponding to each input key is compatible with a conventional telephone keypad. The groups are in an alphabetical order relative to each other.
In still yet another further aspect of the invention, a device is remote from the input keys and receives signals through a wireless transmission. The device can select from a number of key mappings, including a key mapping that is transmitted from a unit containing the input keys.
In yet another further aspect of the invention, the data entry keys have a numeric association and an ordered set of letters from the following group: (2xe2x80x94A, C, B), (3xe2x80x94E, D, F), (4xe2x80x94I, H, G), (5xe2x80x94L, K, J), (6xe2x80x94O, N, M), (7xe2x80x94S, R, P, Q), (8xe2x80x94T, U, V), and (9xe2x80x94Y, W, Z, X).
These and various other features as well as advantages, which characterize the present invention, will be apparent from a reading of the following detailed description and a review of the associated drawings.